Non‐invasive diagnosis of fetal sex; utilisation of free fetal DNA in maternal plasma and ultrasound

Abstract Non‐invasive prenatal diagnosis is now a clinical reality, using both early ultrasound and molecular DNA methods. Technical advances in the sensitivity of the polymerase chain reaction (PCR), coupled with the finding that significant levels of fetal DNA (ffDNA) are found in maternal plasma and serum, has enabled the ready detection of paternally inherited genes or polymorphisms. Routine maternal plasma‐based genotyping is now available for the determination of fetal sex and RHD blood group status (Van der Schoot et al. , 2003). This review touches briefly on the ultrasound diagnoses and then focuses on the application of free ffDNA for fetal sex determination, indicating the Y‐chromosome targets exploited in this strategy and the merits of their utilisation. Copyright © 2006 John Wiley & Sons, Ltd.